The bristlenose plecostomus (Ancistrus spp.) is an intriguing-looking addition to a tropical freshwater aquarium. These small catfish -- which use whisker-like appendages around their mouths to detect leftover fish food and algae -- can help keep a tank clean. Generally peaceful fish, bristlenose plecos do well in a community tank. Breeding bristlenose plecos is not difficult. According to the Pet Education website, you can trigger your plecos to breed by performing a 75 per cent water change in the autumn. You should also provide a breeding cave -- a sheltered area in which the female bristlenose can spawn, and in which the male will conscientiously guard the eggs and fry.
Don thick leather gloves, a dust mask and protective eyewear.
Use an angle grinder, hacksaw or dremmel-type tool to neatly split the flower pot down the middle, forming two vertical halves. Try to cut the pot exactly into two perfect halves; the breeding cave will eventually rest on these cuts on the aquarium floor, so you will want it to lie level.
Place the halves together on their sides, so that each half of the rim -- formerly the top of the pot -- is flush with the other. They should fit neatly together, forming a tunnel that widens towards the middle and narrows at the ends.
Cut an entrance at either end of the two halves so that adult plecos can move in and out freely. You will be cutting the area that was formerly the bottom of the flower pot. According to the Pleco Fanatics website, make the opening wider than the width of the male bristlenose, plus one pectoral fin; the height of the opening should be slightly taller than the fish.
Rinse the dust from the pieces, dry thoroughly and use the silicon gun to glue the pieces together.
Allow the breeding cave to cure for 48 hours, then rinse and place in aquarium. If your plecos are ready to breed, they will begin to make themselves at home. When the eggs are spawned and hatched, the fry will tend to stay attached to the top of cave for a few days, while the male guards the entrance.
Soaking the flower pot for 24 hours makes it easier to cut.
Sometimes the male bristlenose pleco guards the young too enthusiastically -- if 10 days has elapsed since the fry have hatched and they have not emerged from the breeding cave, use a turkey baster to shoot some baby brine shrimp or pulverised fish flakes into the cave.